PubMed Health⌕ Search

Biomedical subjects

M Maass

Publications and source records attributed to M Maass.

At least 55 records · Page 3Linked to original sources
PubMed1998

Poor correlation between microimmunofluorescence serology and polymerase chain reaction for detection of vascular Chlamydia pneumoniae infection in coronary artery disease patients.

Chlamydia pneumoniae has been associated to coronary artery disease by various methods including recovery of viable bacteria from plaques. The pathogenetical relevance of this is unclear but investigation of antichlamydial therapy in coronary arteriosclerosis is already in progress. The microimmunofluorescence test (MIF), the only species-specific serological assay available, might be considered useful in identifying patients with vascular chlamydial infection. However, this has never been systematically examined. We compared levels of C. pneumoniae antibodies in sera using MIF with direct detection of C. pneumoniae in coronary artery segments from 158 patients undergoing myocardial revascularization. A polymerase chain reaction (PCR) protocol, recently evaluated for use with vascular materials, detected C. pneumoniae infection in 34 patients. Correlation of serology and PCR was poor: in relation to PCR. MIF-IgG analysis had 21% sensitivity, 90% specificity, 37% positive predictive value, and 81% negative predictive value for detection of chlamydial presence. Thus, the MIF test currently appears not suitable to predict individual vascular C. pneumoniae infection.

Aged↗
PubMed1998

Endovascular presence of Chlamydia pneumoniae DNA is a generalized phenomenon in atherosclerotic vascular disease.

The common respiratory pathogen Chlamydia pneumoniae has been implicated in the pathogenesis of coronary artery disease and acute myocardial infarction. In order to verify the endovascular presence of potentially viable chlamydia by detection of genomic DNA, we examined atherosclerotic arteries from various vascular regions using a C. pneumoniae specific nested polymerase chain reaction (PCR). The samples were obtained during surgical revascularization procedures or at autopsy. Chlamydial DNA was detected in 51/238 (21%) atherosclerotic samples. A total of 17 non-atherosclerotic control samples were PCR-negative. Chlamydial presence was detected in 36/140 (26%) vascular samples obtained at coronary revascularization procedures, in 9/61 (15%) samples from carotid artery stenosis, 3/17 (18%) samples from the aorta, and 3/20 (15%) iliac artery samples. Histomorphological discrimination of infected and non-infected arterial samples was not possible. Antichlamydial IgG and IgM response as examined by microimmunofluorescence assay did not aid identification of individual endovascular infection. C. pneumoniae is present in a significant proportion of atherosclerotic arteries. Its occurrence in atheromatous plaques is not limited to coronary arteries and may be considered indicative of an infectious component in atherosclerosis. However, it remains unclear whether chlamydia actually initiates atherosclerotic injury, facilitates its progression, or merely colonizes pre-existing atheromata.

Adult↗
PubMed1998

Tropical rat mite dermatitis: case report and review.

Six medical students inhabiting a centuries-old, rat-infested house in Lübeck, in northern Germany, were suffering from itching papules and seropapules. Prior to these patients' visit to our institute, their conditions had been diagnosed as pediculosis, scabies, or pulicosis and treated unsuccessfully with the antiparasitic agent lindane (0.3%). The final diagnosis, tropical rat mite dermatitis, was based on the identification of the arthropod Ornithonyssus bacoti, which has an unsegmented body with eight legs. No treatment was recommended, and the dermatitis disappeared within 2 weeks. Measures taken to prevent reinfestation included extermination of the rats and treatment of the rooms of the house with the acaricide benzyl benzoate. Because the mite O. bacoti spends a relatively short time on a host and penetrates the skin for feeding only, the application of an antiparasitic agent is not necessary. If indicated, treatment should be symptomatic.

Adult↗
PubMed1998

In vitro susceptibilities of Chlamydia pneumoniae strains recovered from atherosclerotic coronary arteries.

Chlamydia pneumoniae strains have been recovered from arteriosclerotic coronary arteries, but their antibiotic susceptibility profiles have not yet been examined. We report in vitro susceptibility data for five cardiovascular C. pneumoniae isolates. These strains did not differ significantly from respiratory strains in their patterns of susceptibility to azithromycin, erythromycin, roxithromycin, ofloxacin, doxycycline, rifampin, and penicillin G. Roxithromycin was the most active macrolide, and rifampin was the most effective drug overall.

Chlamydophila pneumoniae↗
PubMed1998

Interaction of Chlamydia pneumoniae and human alveolar macrophages: infection and inflammatory response.

The obligate intracellular pathogen Chlamydia pneumoniae is associated with chronic respiratory, atherosclerotic, and rheumatic disease. The alveolar macrophage (AM) is a potential target cell for the pathogen and may contribute to respiratory immunopathology. We therefore investigated in vitro the interaction between chlamydiae and macrophages with cocultures of C. pneumoniae and AM from 12 healthy volunteers. Inflammatory responses were evaluated through lucigenin-amplified chemiluminescence; secretion of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin 8 (IL-8); and expression of intercellular adhesion molecule-1 (ICAM-1) and human leukocyte antigen-DR (HLA-DR). C. pneumoniae readily induced productive infection in the AM. Inclusions containing replicating pathogens could be maintained for up to 120 h. Morphologically similar infection patterns were seen ex vivo in AM collected from six patients with known C. pneumoniae pneumonia. AM responded to the infection with a marked, dose-dependent release of reactive oxygen species, TNF-alpha, IL-1beta, and IL-8. ICAM-1 expression remained unchanged, but HLA-DR was significantly upregulated. Our data indicate that the release of antimicrobial mediators cannot prevent chlamydial infection and replication in AM, but may be involved in amplification of the local inflammatory response in C. pneumoniae pneumonia.

Adult↗
PubMed1997

Cardiovascular disease risk from prior Chlamydia pneumoniae infection can be related to certain antigens recognized in the immunoblot profile.

Chlamydia pneumoniae infection has been described as a risk factor for atherosclerosis on the basis of raised seroreactivity against complete elementary bodies among cardiovascular disease (CVD) patients. In order to identify antigens of possible pathogenetic relevance, C. pneumoniae IgG and IgA immunoblot profiles were compared for CVD patients (IgG: n = 159; IgA: n = 72) and for controls (IgG: n = 158; IgA: n = 115), all with prior C. pneumoniae infection. IgG and IgA recognition patterns were very similar, and a broad range of antigens was commonly recognized. However, statistical analysis demonstrated IgG seroresponses to 40, 54, 60, 75, and 98 kDa antigens to be more frequent among patients and resulting in odds ratios between 2.3 (98 kDa) and 29.4 (40 kDa) for development of CVD. This relation remained evident after adjustment for age and sex. Cardiovascular risk from prior chlamydial infection can thus be linked to certain antigens. Thus, for the first time potential atherogenetic virulence factors of C. pneumoniae are described. Though causal relation of chlamydial and atherosclerotic disease cannot be proven yet, evidence is growing that chlamydial structures play a part in the multifactorial pathogenesis of one of the most prevalent health hazards world-wide.

Antigens, Bacterial↗
PubMed1997

Endovascular presence of Chlamydia pneumoniae in patients with hemodynamically effective carotid artery stenosis.

The bacterial pathogen Chlamydia pneumoniae has been associated with atherosclerosis. Recent studies have reported chlamydial antigen to be present in atherosclerotic coronary arteries, but this relation has not yet been widely accepted. In order to verify an endovascular presence of potentially viable chlamydiae by detection of genomic DNA, the authors examined atherosclerotic carotid arteries by using a C. pneumoniae-specific nested polymerase chain reaction. Chlamydial DNA was detected in 9 of 61 (15%) arterial samples obtained from therapy of hemodynamically effective cervical vascular stenosis. Chlamydial presence was limited to advanced atherosclerotic lesions (P < or = 0.02): tissues from the same arteries with early subendothelial lesions did not harbor the pathogen. Thus, an etiologic role of C. pneumoniae is more plausible for progression than for initiation of atherosclerotic lesions. Histomorphologic discrimination of infected and noninfected samples was not possible and serology was unrewarding in detecting the infected patients. Chlamydial occurrence in atheromatous plaques is apparently a general phenomenon of atherosclerosis not limited to coronary arteries. Endovascular presence of genomic DNA of a bacterial pathogen susceptible to antimicrobial agents encourages thought on a new approach to prevent progression of atherosclerosis in a substantial proportion of patients. However, an etiologic contribution of C. pneumoniae in the multifactorial process of atherogenesis yet remains to be demonstrated.

Aged↗
PubMed1996

Chlamydia pneumoniae pneumonia in hospitalized patients. Clinical characteristics and diagnostic value of polymerase chain reaction detection in BAL.

STUDY OBJECTIVE: To evaluate the incidence and clinical characteristics of Chlamydia pneumoniae infection as detected by polymerase chain reaction (PCR) and culture of BAL in hospitalized patients with pneumonia, HIV-infected persons, and control subjects. DESIGN: Prospective, comparative clinical study. SETTING: University hospital medical center. PATIENTS: Fifty-seven hospitalized patients with acute lower respiratory tract infection (group 1); 47 HIV-positive patients (group 2); 100 patients with noninfectious bronchopulmonary disorders (group 3). INTERVENTIONS: BAL was performed in all patients at hospital admission for diagnostic purposes. In addition to semiquantitative bacterial and fungal culture, isolation and detection of C pneumoniae were performed by cell culture and PCR of the lavage fluid. MEASUREMENTS AND RESULTS: C pneumoniae was detected in 16% of group 1, 13% of HIV-positive persons, and 0% of control subjects. The sensitivity of chlamydial culture was much lower as compared with PCR (4 vs 15 cases). In contrast to group 1, in the HIV-positive patients, acute respiratory symptoms were not always present, and in 3 of 6 cases, copathogens were found in the BAL. BAL differential cell counts disclosed a significant lymphocyte elevation mostly due to the CD8 subset (group 1: 15% vs 5%; group II: 18.5% vs 4%; C pneumoniae positive vs negative cases, respectively). CONCLUSIONS: C pneumoniae is frequently detected in the BAL of hospitalized patients with pneumonia as sole pathogen. PCR detection is highly specific and far more sensitive than cell culture. Asymptomatic carriage seems to be uncommon in immunocompetent patients, but does occur in HIV-positive patients. A lymphocytic alveolitis is frequently found by BAL cytologic study and may represent a T-cell response to chlamydial infection in the lower respiratory tract.

AIDS-Related Opportunistic Infections↗
PubMed1995

Evaluation of culture conditions used for isolation of Chlamydia pneumoniae.

As only a few viable strains of the frequent respiratory pathogen Chlamydia pneumoniae have been isolated worldwide, improvement and standardization of isolation procedures is mandatory for adequate diagnosis and recovery of strains for further investigation. Growth rates of eight C pneumoniae strains were assessed for five host cell lines, for the growth-promoting effect of host cell cytostasis, for infection of adherent or suspended host cells, for optimal first passage incubation time, and for use of multiple blind passages. Cycloheximide-treated HEp-2 or NCI-H 292 monolayers appeared most sensitive for isolation of C pneumoniae. No significant improvement of sensitivity was achieved by extending first passage incubation periods from 3 to 7 days. In contrast, continuous propagation in 4 culture passages yielded on average a 7-fold enhanced chlamydial recovery. Additional comparative isolation of two wild-type strains showed highest inclusion counts in HEp-2 cells, but subculture was necessary for optimal sensitivity. A widely applicable protocol using tissue culture plates for isolation of C pneumoniae is suggested.

Cell Division↗
PubMed1995

Transport and storage conditions for cultural recovery of Chlamydia pneumoniae.

Chlamydia pneumoniae is characterized by rapidly decreasing viability outside the host cell, and efficient preservation of its infectivity is a prerequisite for subsequent cell culture recovery. Extracellular survival of three C. pneumoniae stock strains and three wild-type strains subjected to simulated conditions of transport was therefore examined in order to establish recommendations for transport and storage of clinical specimens. The presence of fetal calf serum in transport media as well as refrigeration distinctly improved chlamydial retrieval during prolonged transport. Loss of infectivity was kept to a minimum in Eagle's minimal essential medium or sucrose-phosphate-glutamine medium. Storage at 22 degrees C permitted a stock strain recovery of 81% after 12 h. When refrigeration to 4 degrees C was provided, recovery rates of 74% could be achieved after 48 h. Though the strains were from different geographic regions, requirements for good survival were comparable and should therefore apply worldwide. The results indicate that the laboratory strains are not extremely labile. However, comparative examination of the wild-type strains showed less stability: primary isolates were not satisfactorily retrievable beyond 4 h at 22 degrees C or beyond 24 h at 4 degrees C. Further extension of storage times resulted in rapidly decreasing recovery, indicating a requirement to freeze samples at -75 degrees C to preserve viability. Adherence to the shorter storage periods suggested by the data obtained with primary isolates is recommended to ensure successful transport until more extensive testing with clinical materials is available.

Bacteriological Techniques↗
PubMed1994

[Isolation of Chlamydia pneumoniae in atypical pneumonia].

A 33-year-old man, who two months previously had been treated for bronchopneumonia with cefuroxime, fell ill again with cough, dyspnoea and fever up to 39.8 degrees C. Auscultation and lung function tests indicated respiratory tract obstruction. The chest radiograph revealed an infiltrate of the left lower lobe and bronchoscopy showed hypertrophic bronchitis. Empirical antibiotic treatment with clarithromycin (initially 500 mg twice daily, continued on half this dose) lead to rapid improvement of clinical symptoms and the patient could be discharged after 9 days. A follow-up examination 3 months later showed no abnormality. A cell culture procedure using bronchoalveolar lavage fluid obtained during bronchoscopy permitted the continuous demonstration of Chlamydia pneumoniae inclusions in HEp-2 host cells by immunofluorescence microscopy. In parallel, Chlamydia pneumoniae DNA was specifically demonstrated in the lavage fluid by use of the polymerase chain reaction. This is the first reported isolation of a replicative Chlamydia pneumoniae strain in Germany.

Adult↗
PubMed1994

Comparison of sample preparation methods for detection of Chlamydia pneumoniae in bronchoalveolar lavage fluid by PCR.

Amplification inhibitors can lead to false-negative results for PCR. In order to evaluate the reliability of PCR for the detection of Chlamydia pneumoniae, the presence of PCR inhibitors in 75 bronchoalveolar lavage specimens was assessed after treatment by various sample preparation methods. Specimens were collected from patients with acute respiratory infections, including four cases of proven C. pneumoniae infection. Substances inhibitory to the amplification of chlamydial DNA continued to be present in 12% of the samples treated according to the commonly used single-step proteinase K digestion and in 31% of the samples processed by heat treatment. However, the complexing of DNA-contaminating proteins and polysaccharides from digested specimens to cetyltrimethylammonium bromide (CTAB) followed by DNA extraction efficiently removed inhibitors from all experimental samples and provided subsequent identification of all positive clinical samples by PCR. The CTAB method and proteinase K treatment had comparable detection limits of approximately 0.01 inclusion-forming units. CTAB-based DNA purification of respiratory specimens is recommended to increase the diagnostic sensitivity of PCR and confidence in negative results.

Bronchoalveolar Lavage Fluid↗
PubMed1993

Growth in serum-free medium improves isolation of Chlamydia pneumoniae.

Infectivity titers were determined for eight Chlamydia pneumoniae strains simultaneously grown in serum-free and serum-supplemented cell culture media. Use of serum-free medium resulted in a 10- to 50-fold increase in the susceptibility of HL cells to chlamydial infection. Comparative primary isolation of a wild-type strain also produced higher inclusion counts in a serum-free environment. Serum-free cultivation is recommended to increase the efficiency of C. pneumoniae isolation from clinical material and to permit elementary body purification without interference caused by serum components.

Chlamydophila pneumoniae↗
PubMed1992

Detection of Bartonella bacilliformis in cultures, blood, and formalin preserved skin biopsies by use of the polymerase chain reaction.

A polymerase chain reaction (PCR) is described for the detection of Bartonella bacilliformis, the etiologic agent of bartonellosis, which cannot be identified biochemically. Amplification of a genomic 231 bp Bartonella DNA sequence permitted specific identification of 12 Bartonella isolates from Peruvian bartonellosis patients as well as detection of Bartonella DNA in blood samples and formaldehyde preserved skin biopsies. Specificity of amplification products was confirmed by restriction fragment analysis. No positive results were obtained with Brucella abortus, phylogenetically closely related to B. bacilliformis, and several other bacterial, fungal, and protozoal species. PCR appears as a promising technique for specific identification of B. bacilliformis in cultures and in clinical materials with further applications in taxonomic studies and in the investigation of Bartonella-like isolates obtained outside South America.

Bacteremia↗
PubMed1992

Isolation of an immunodiagnostic Taenia solium coproantigen.

Antigens of Taenia solium can be demonstrated by ELISA technique in stool samples of tapeworm carriers. In order to isolate these immunodiagnostic components from stool, fecal samples of known T. solium carriers were subject to chromatographic purification procedures: immunoaffinity chromatography and a subsequent two-step high performance liquid chromatography yielded a 60-kDa protein that was shown to react in a Western blot with polyclonal anti-T. solium IgG. The protein isolated appeared to be the major antigenic component excreted with the feces of parasite hosts.

Animals↗
PubMed1991

Detection of Taenia solium antigens in merthiolate-form preserved stool samples.

Cysticercosis can be controlled by mass treatment of Taenia solium carriers in hyperendemic areas. An automated screening method suitable for mass application is required to determine the prevalence of taeniasis and the efficacy of its treatment, since existing methods of carrier detection are considered insufficient for this purpose. Thus, a biotin/avidin-enhanced enzyme-linked immunosorbent assay (ELISA) was designed, which detected T. solium antigens in supernatants of merthiolate-formalin preserved stool samples. The assay distinguished the nine T. solium carriers tested from 41 negative controls, but cross-reactivity with Taenia saginata was noted.

Animals↗
PubMed1989

[Interactions of detergents with phospholipid bilayers at sublytic concentrations--partition or binding?].

Using the bubble pressure method the interaction of liposomes with detergents at sublytic concentrations was studied. The results are discussed in terms of a partition or binding model. The findings support an equilibrium partition of the surfactant between the aquous and lipid phase. For some detergents, however, concentration dependent partition coefficients were found.

Chemical Phenomena↗